Drag coupling between a thin Al film and a two-dimensional electron gas near the superconducting transition

We studied a bilayer system consisting of a two-dimensional electron gas in a GaAs/AlGaAs heterostructure and a thin superconducting Al film. Our goal was to probe the coupling between the electrons and the thermally excited vortices present near the superconducting transition temperature. Drag measurements were made by passing current through the superconducting layer and measuring the voltage induced in the two-dimensional electron gas. Our measurements indicated no drag voltage, down to less than View the MathML source, in any of our devices. From this we deduce an upper limit on the drag resistance of View the MathML source. These results were unaffected by varying the properties of the two-dimensional electron gas or the drive current.